A clutch is a device which is controlled by, e.g., variations in the engine driving condition of vehicle. There are provided clutches which open or close valves typically in an electromagnetic manner.
Conventional electromagnetic clutches are configured to freely and properly control the fan rotating speed by precisely adjusting the fluid flux according to various operation conditions in a simplified structure capable of reducing power consumption while operating valves using an electromagnetic force created by an electromagnet (Korean Patent No. 10-0370445).
Such a conventional electromagnetic clutch is operated to close the fluid outlet of the valve when electric current is supplied to the electromagnet and open the fluid outlet of the valve when the supply of electric current is cut off. To ensure that the valve is operated so, a separate permanent magnet is inevitably required, which restricts the simplification of the internal structure.
Further, conventional clutches are configured to allow an elastic means to directly open and close the fluid outlet. Since the elastic means is made of metal, such as carbon steel, it is difficult to make sure the opening and closing of the fluid outlet.
Prior technical documents in the art to which the present invention pertains include Korean Patent No. 10-0370445 and Korean Patent No. 10-1305399.